The advantages of delivering a liquid, particularly a perfume, from an encapsulate system are well documented in the literature. Some of the advantages attained by encapsulating a liquid include the enablement of controlled and/or sustained delivery of the liquid from products comprising encapsulates, the ability to enhance the stability of a liquid such as perfume and the possibility of protecting and segregating incompatible ingredients. Many different encapsulate systems and preparations thereof have been developed, which find application in numerous consumer products, such as, for example, laundry and cleaning preparations, cosmetic compositions such as creams, lotions, gels and the like and personal care preparations such as deodorants, antiperspirants and shower gels, amongst others.
WO 98/28398 describes water-insoluble particles comprising an organic polymer and imbibed liquid having a hydroxy functional polymer at the exterior of the particles. The imbibed liquid is preferably perfume, although sunscreening agents are also mentioned as a possibility. The organic polymer particles are described as solid particles (but possibly also porous solid) and the hydroxy functional polymer which may form a complete or incomplete coating on the particle is described as enhancing the deposition and/or retention of the particles on various surfaces. Further, the attachment of the hydroxy functional polymer to the particles is described such that the polymer is not completely removed upon contact with water and may be chemically bonded with the core polymer. Desirably, according to the required use, the imbibed liquid is retained in the particles and released slowly therefrom.
WO 98/28396 discloses products, such as for example, solid or liquid laundry detergent compositions, rinse conditioning liquids, or bars for personal washing, containing an active ingredient and the particles described in above-mentioned WO 98/28398.
EP-B-441,512 relates to a swellable oil-absorbent cross-linked polymer obtained by polymerising at least 90% by weight of a monomer having as its main moiety an alkyl (meth) acrylate and from 0.001 to 10% by weight of cross-linkable monomer. The cross-linked polymer is described as absorbing a wide range of oils including aromatic components.
Particles comprising polymers as hereinabove described may be effectively employed in products which are in liquid form, such as for example, rinse conditioners. In these types of products, the dynamics of the system are such, that if the absorbed or imbibed perfume of the particle is lost to the liquid carrier of the product, the lost perfume may be replaced by further perfume contained in the liquid carrier. A system may be devised, such that the equilibrium favours a high proportion of the imbibed perfume to reside in the particles thus enhancing the amount of perfume delivered to a desired surface.
However, it has been found that when such particles are employed in dry products, e.g. granular laundry powders, the particles typically demonstrate a limited useful lifetime. If the imbibed liquid is for example perfume, the perfumery ability of the particle is lost upon storage, with the perfume evaporating or slowly being released from the particle to the atmosphere or surrounding laundry powder base. Once released, there is no mechanism in a dry product for returning the perfume to the particle. This effect is disadvantageous in products intended for use in laundry applications for example, where it is desirable to deliver fragrance to a fabric surface of an article upon washing, and a lingering and prolonged fragrance during the storage of laundered articles.
WO 98/12291 relates to a laundry additive particle suitable for use in a laundry or cleaning composition comprising a porous carrier core (into which perfume may be incorporated) encapsulated within two surface coating layers of specified materials having specified physical properties, wherein the particle has a hygroscopicity value of less than 80%. The porous carrier may be any of a number of porous solids, but is preferably a zeolite. The encapsulating materials of the first coating layer are derived from at least one partially water-soluble hydroxylic compound including for example, carbohydrates e.g. simple sugars, polysaccharides and starches, amongst others, and natural and synthetic gums. The encapsulating materials of the second coating layer are carbohydrates which optionally may include other additives.
WO 98/41607 relates to particles and compositions thereof, comprising glassy particles containing agents useful for laundry and cleaning applications, such as for example, perfume. The glassy particle comprises a glass derived from at least one partially water-soluble hydroxylic compound having specified physical properties and possibly also a perfume carrier material when the laundry and cleaning agent is perfume. Suitable perfume carrier materials include porous solids, preferably zeolites.
WO 97/47720 relates to a process for preparing a particulate laundry additive composition for perfume delivery in laundry and fabric softening products, comprising porous carrier particles loaded with perfume and encapsulated within appropriate material comprising a pigment. As per WO 98/12291 and WO 98/41607 described above, the porous carrier material is a porous solid and is preferably a zeolite.
The use of a porous carrier material in a particle such as described in the above-mentioned art may not result in the desired fragrance impact delivered to, and maintained on, laundered or cleaned articles. Porous materials such as zeolites may release perfume rapidly upon contact with water, thus reducing the amount of perfume residing in the particles upon deposition on a surface e.g. fabric surface of an article from the wash liquor or rinse.